The way file timestamps (modification and access times) have changed,
to fix inaccuracies introduced by the old way. Times are now stored
as two integers giving full seconds and nanoseconds past the full
second, instead of the weird earlier system that was imposed by Python's
use of floating point for the timestamps. This causes the repository
format version to be bumped, resulting in a need to start over with an
empty repository.

Extended file attributes are now backed up from and restored to local
filesystems. They are neither backed up, nor restored for live data
accessed over SFTP.

If the --exclude regular expression is wrong, Obnam now gives an
error message and then ignores the regexp, rather than crashing.

There is now a compression plugin, enabled with --compress-with=gzip.

De-duplication mode can now be chosen by the user: the new
--deduplicate setting can be one of never (fast, but uses more space);
verify (slow, but handles hash collisions gracefully); and
fatalist (fast, but lossy, if there is a hash collision). fatalist
is the default mode.

Restores now obey the --dry-run option. Thanks to Peter Palfreder for
the bug report.

New option --verify-randomly allows you to check only a part of the
backup, instead of everything.

Verify now has some progress reporting.

Forget is now much faster.

Forget now has progress reporting. It is not fast enough to do without,
sorry.

Backup now removes any checkpoint generations it created during a backup
run, if it succeeds without errors.

BUG FIXES:

Now works with a repository on sshfs. Thanks to Dafydd Harries for
reporting the problem.

Now depends on a newer version of the larch library, fixing a problem
when the Obnam default node size changes and an existing repository
has a different size.

User and group names for sftp live data are no longer queried from the
local system. Instead, they're marked as unknown.